No Micro or Nano SIMs yet. 3G still mostly on AWS band. No international calling. No way to extend life of SIM.

Bottom Line

Have an unlocked phone? Ready SIM cards are an easy choice for short trips or anonymous mobile Internet use.

Need a burner? I won't judge. Maybe you want to hand out a semi-bogus number to intriguing guys at nightclubs. Maybe you're just in the U.S. for a few days, visiting. Ready SIM cards from Roam Mobility feed your need for disposable mobile phone numbers with a quick and easy, grab-and-go solution that works with any unlocked handset.

Plans and SetupReady SIM offers seven different plans. Unlimited talk and text SIMs with no data support run $15 for 3 days, $20 for a week, $25 for two weeks, or $40 for 30 days. With data, you'll pay $25 for a week with 500MB, $35 for two weeks with 1GB, and $55 for 30 days with 2GB. Prices are competitive with other operators.

When I say grab and go, I mean it: Ready SIM doesn't require any ID, subscription, signup, email address, or other form of contact. You don't have to talk to anyone to set it up. It's completely anonymous and self-activating, as far as the law provides. And when your time is up, well, you just dispose of the card.

Right now, Ready SIM comes only in the standard SIM size. Convertible standard/MicroSIMs will be available in March, with iPhone 5-compatible nanoSIMs coming in April.

I used Ready SIM in a range of feature phones and Android-powered smartphones. Setup was easy: Pop in the SIM, text a ZIP code to 7850, and get back a local phone number for that ZIP code. Trying two SIMs, I got a 415 number for the 94101 zip code and a 646 number for 10010. I got a text with my phone number and the SIM's expiration date, and I was on my way.

With data plans, there's one extra step: You need to create a new APN called "roam" and save it. That was easy enough to do in the networking settings of my Android phones.

There's no account management at all, and no cash balance on the SIM. All plans offer unlimited talk in the U.S., both domestic and international text, and voice mail. You can't make international calls, although you can receive them. Things get a little tricky with the data plans, as Roam doesn't give you a way to monitor your data usage. If you have an Android phone, I'd suggest immediately downloading the Onavo Count app, which keeps track of your data usage. In April, the company says it will start sending customers an SMS warning when they're down to 10 percent of their allotted data. If you run out of data, you can't add more; you just have to get another SIM.

SIMs can't be renewed, either, at least for now. Roam says that in March you'll be able to extend SIMs with top-up cards within 72 hours of their expiration time. If you like your number, you can port it out to another, longer-term provider.

Network and PhonesReady SIM uses T-Mobile's nationwide HSPA+ 42 network. For international travelers, that can be a bit of a downer. While T-Mobile is busily converting its 3G network onto the internationally compatible 1900MHz band, most of T-Mobile's 3G network is still on the AWS band. That means in most of the country, international-spec phones will be stuck on the slower 2G EDGE system, getting Internet speeds of about 100-120kbps. If you can find a T-Mobile-compatible phone, speeds will be dramatically higher, as much as 6-8Mbps down.

Ready SIM doesn't offer any phones itself, relying on independent dealers. One of them, Social Mobile, sells phone-and-SIM packs through readysimgo.com, but the phones are overpriced. Frankly, you're better picking up the cheapest possible GSM phone on Amazon or eBay. Decent phones with QWERTY keyboards from major manufacturers like Samsung and Huawei should start around $40.

If you're looking for inexpensive smartphones for this service, Amazon has the motherlode. Consider the $99.99 Huawei U8150, the $164.99 HTC G2 Vision, or a whole bunch of BlackBerrys, for instance. Ready SIM will also work with any T-Mobile phone.

Terms, Privacy, and ConclusionsFor better or for worse, Ready SIM's privacy is bound by U.S. law. That means Roam Mobility has to keep records of every call made to or from a Ready SIM for seven years after a SIM is deactivated, and has to hand those over to law enforcement with a court order. If you buy your Ready SIM with cash over the counter, though, Roam has no idea who you are, and can't connect your call details with your identity.

Internet traffic is safer. All Ready SIM data goes through a private APN which routes traffic through a proxy server, so it looks like all Web requests are just going to the proxy server. Presumably, a court could subpoena the proxy server, but once again, if you buy your Ready SIM with cash, Roam doesn't know who you are.

Ready SIM is a unique product: a short-term SIM with a real focus on privacy. Since it's time-limited, it's best used for a specific trip, task, or project. If you're looking for longer-term GSM prepaid service, check out our roundup of the Best Prepaid SIM Cards. The service clearly still has some growing to do–we'd like to see those MicroSIMs, as well as some way to top up data allowances. But in its focus on privacy, Ready SIM is unique.

About the Author

PCMag.com's lead mobile analyst, Sascha Segan, has reviewed hundreds of smartphones, tablets and other gadgets in more than 13 years with PCMag. He's the head of our Fastest Mobile Networks project, hosts our One Cool Thing daily Web show, and writes opinions on tech and society.
Segan is also a multiple award-winning travel writer. Other than ... See Full Bio

Ready SIM

Ready SIM

Get Our Best Stories!

This newsletter may contain advertising, deals, or affiliate links. Subscribing to a newsletter indicates your consent to our Terms of Use and Privacy Policy. You may unsubscribe from the newsletters at any time.